Skeletal Radiology最新文献

Soft tissue-RADS scoring system for musculoskeletal (MSK) tumor and tumor-like lesions is recently published. The system includes diagnostic MRI flowcharts and algorithms for lipomatous masses, cyst-like or high-water content masses, and indeterminate-solid appearing masses with consistent and standardized management recommendations. MSK radiology and cancer imaging training commonly provides the essential skills needed to render appropriate prospective diagnosis for many non-neoplastic tumor-like lesions and various commonly encountered sarcomas. Such trained readers may benefit from additional advanced algorithms to accurately identify and categorize different benign tumors and sarcomas and correctly input them in the soft tissue-RADS scoring system. These algorithms are built from a comprehensive literature search to establish an evidence-based composite and are supported by the expert opinions of the multidisciplinary ACR-soft tissue-RADS team. In this article we provide (1) a literature review of multimodality imaging, immunopathology, and clinical findings of soft tissue tumors and tumor-like lesions, presented in 7 tables (condensed from the 12 tables published in the WHO classification of soft tissue tumors) with respective table summaries; (2) a suggested modality-based lexicon; and (3) advanced diagnostic algorithms for trained readers based on published evidence and expert opinion that feed into the soft tissue-RADS scoring system (categories 1-6). The purpose of this work is to provide comprehensive guidance on soft tissue-RADS scoring to help streamline care for soft tissue tumors and tumor-like lesions and optimize patient outcomes.

The immature sacroiliac joint (SIJ) has developmental imaging appearances that frequently simulate sacroiliitis in children and adolescents evaluated for juvenile spondyloarthritis, and false-positive interpretation increases when adult MRI and structural criteria are applied. This review integrates developmental anatomy with MRI and CT findings and discusses CT-like MRI and MRI-based synthetic CT as structural adjuncts for cortical assessment in the immature SIJ. We emphasize the most relevant false-positive pathways in daily practice, including peri-physeal fluid-sensitive marrow hyperintensity, developmental cortical contour variants, transitional intersegmental fusion interfaces, well-corticated intra-articular developmental ossification centers, physiologic enhancement patterns, and intra-articular gas (vacuum phenomenon). The review also outlines modality-specific strengths and limitations and provides practical guidance on how to integrate fluid-sensitive and structural information across modalities. The figure set is organized as a teaching atlas focused on pattern recognition, multimodality correlation, and explicit interpretive safeguards to help radiologists distinguish physiologic maturation from true inflammatory disease in skeletally immature patients.

Objective: To assess the association between opportunistically derived CT measures of psoas muscle quality and lumbar osteoporosis in patients undergoing total hip arthroplasty.

Materials and methods: This retrospective cohort study included 220 total hip arthroplasty candidates who underwent preoperative lumbar dual-energy X-ray absorptiometry and unenhanced CT at L3. Psoas muscle attenuation, psoas muscle index, and vertebral trabecular attenuation were quantified using standardized protocols. Multivariable logistic regression was used to evaluate associations with lumbar osteoporosis (T-score < -2.5), adjusting for age, sex, and body mass index. The association between preoperative psoas muscle attenuation and postoperative Hip Disability and Osteoarthritis Outcome Score-Joint Replacement was examined using multivariable linear regression adjusting for baseline score.

Results: Lumbar osteoporosis was present in 71 patients (32%). After adjustment, each 10-HU decrease in psoas muscle attenuation (adjusted odds ratio 1.28, 95% confidence interval 1.05-1.56, P = 0.024) and vertebral trabecular attenuation (adjusted odds ratio 1.21, 95% confidence interval 1.05-1.39, P = 0.035) was associated with higher odds of osteoporosis. At a median follow-up of 24 months (interquartile range, 16-33 months), higher preoperative psoas muscle attenuation was independently associated with higher postoperative Hip Disability and Osteoarthritis Outcome Score-Joint Replacement score (β = 1.02 per 1-HU increase, 95% confidence interval 0.62-1.43, P = 0.018).

Conclusion: Lower psoas muscle attenuation on opportunistic CT was associated with lumbar osteoporosis and postoperative functional outcomes in patients undergoing total hip arthroplasty. These findings support the potential role of CT-derived attenuation metrics as complementary markers in preoperative evaluation.

Although most imaging assessments are made qualitatively, quantitative measurements in orthopedic imaging are becoming more important in detecting subtle findings and assessing degrees of abnormality, which can help direct surgical management. In the knee, patellofemoral maltracking is a common cause of anterior pain, particularly in younger patients. Failure to recognize this pathophysiology may result in accelerated chondral loss and osteoarthritis (OA), and the imaging findings may be subtle. As a result, clinicians and radiologists have developed numerous measurements to detect and quantify patellofemoral alignment. Additional entities, such as femorotibial subluxation or angular abnormalities, may only be detected by using standardized measurements and can help detect ligamentous insufficiency or developmental malalignment, which can lead to instability and OA in the medial and lateral femorotibial compartments. Finally, the proper positioning and hardware selection for knee arthroplasty are critical to preventing early hardware failure and postsurgical pain. This review, which focuses on the knee, is the second in a three-part series discussing the appropriate imaging modalities on which to obtain specific lower extremity measurements as well as proper measurement techniques, grouped by pathology. Furthermore, the normal value or range of values according to current literature is reported, along with the significance of abnormal measurements.

Objectives: To analyze the added value of Zero Echo Time (ZTE) MRI compared with a standard MRI protocol in detecting osseous alterations in diabetic foot. To compare ZTE performance with CT for detecting osseous abnormalities and to evaluate inter-observer reproducibility using Cohen's kappa coefficient.

Materials and methods: This retrospective study included 46 patients (33 men, 13 women; median age, 64 years) with clinically confirmed diabetes mellitus and clinically suspected diabetic foot complications. A standard MRI protocol including a ZTE sequence was performed in all patients; all patients also underwent CT for comparison. Three readers (two radiologists and one radiology resident) independently assessed image quality and osseous abnormalities, including bone erosions, bone and soft tissue pneumatosis, dislocations, and sclerosis. Sensitivity, specificity, accuracy, and inter-observer agreement (Cohen's κ) were calculated.

Results: ZTE demonstrated superior detection in almost all osseous alterations compared with the standard MRI protocol, with the exception of bone exposure and erosions, where performance was comparable. Image quality of ZTE was rated as good to excellent in the majority of examinations. Inter-observer agreement for ZTE was excellent between the two musculoskeletal radiologists and ranged from moderate to excellent between the senior radiologist and the resident. ZTE showed high concordance with CT for detection of bone abnormalities.

Conclusion: ZTE significantly improves detection of osseous alterations in diabetic foot, even under suboptimal imaging conditions. Its high image quality and strong inter-reader agreement support integration into standard MRI protocols for improved bone assessment.

Intra-articular gas is a recognized mimic of meniscal tears on knee MRI, typically resulting from a vacuum phenomenon caused by joint distension and negative intra-articular pressure. This study presents three cases demonstrating transient intra-articular gas that simulated meniscal pathology but was ultimately identified as a benign vacuum phenomenon. We describe a novel diagnostic clue, the "rising tide sign," which refers to the progressive disappearance of intra-articular gas and the posterior-to-anterior migration of the fluid interface in a gravity-dependent manner, resembling rising tidal water. Recognition of this sign enables differentiation between true meniscal tears and gas artifacts, thereby avoiding false-positive diagnoses and potential unnecessary surgical intervention.

This review examines osteonecrosis (ON) in elite athletes, encompassing bone infarcts (BI) in the medullary canal of the metaphysis or diaphysis and epiphyseal subchondral avascular necrosis (AVN), which is more likely to lead to joint collapse. Unlike in the general population where systemic disease and trauma are primary causes, chronic repetitive microtrauma and stress-related injury are significant contributors in athletes. This review therefore distinguishes between primary ON and secondary ON, which develops on a background of stress or insufficiency fractures, relevant in this population. This review also highlights the paradigm shift in the understanding of "spontaneous osteonecrosis of the knee" (SONK), now recognized as a subchondral insufficiency fracture with secondary ON on the continuum of stress-related injuries rather than as an idiopathic, isolated event. The role of corticosteroids is analyzed, distinguishing the well-established risk from systemic use from the more controversial, incompletely defined link to local intra-articular injections, noting the contraindication of injections in certain pathologies like sesamoid AVN. Finally, this review emphasizes the crucial role of MRI for early detection and staging of ON in elite athletes and the importance of tailored management strategies, which begin with conservative measures but may necessitate career-altering surgical interventions in advanced stages. The prognosis for return to sport is often guarded, underscoring the need for a holistic approach that addresses both biomechanical loading patterns and systemic risk factors.

Ceramic-on-ceramic bearings are widely used in total hip arthroplasty (THA); although rare, ceramic femoral head fracture represents a serious complication. This event typically occurs early or after trauma, whereas atraumatic late-onset fractures confined to the femoral head component are exceedingly uncommon. A 73-year-old patient developed sudden-onset hip pain and functional impairment 11 years after a primary ceramic-on-ceramic THA. The patient denied any preceding trauma. Radiographs demonstrated multiple ceramic fragments without clear identification of the donor site; intraoperative inspection confirmed a fractured femoral head with an intact liner. Revision surgery was performed with complete removal of ceramic debris and exchange to a new ceramic femoral head using a taper adapter while preserving the well-fixed stem. The postoperative course was uneventful, and the patient regained satisfactory function at follow-up. This case represents an exceedingly rare late atraumatic fragmentation of a ceramic femoral head in a ceramic-on-ceramic THA, with successful stem-preserving revision despite extensive intra-articular ceramic debris. Orthopedic surgeons and musculoskeletal radiologists should remain vigilant for this possibility in patients presenting with acute hip symptoms years after implantation. Prompt recognition and revision surgery are essential to achieve favorable outcomes.